Supplementation of dietary omega-3 polyunsaturated fatty acids (“ω-3 PUFAs”) such as eicosapentaenoic acid, a component of fish oils, may have beneficial effects in diseases such as arteriosclerosis, arthritis, asthma and cancer, which may be mediated by antithrombotic, immunoregulatory and anti-inflammatory responses [De Caterina, R., S. Endres, S. D. Kristensen, and E. B. Schmidt, editors. (1993). n-3 Fatty Acids and Vascular Disease. Springer-Verlag, London; Lands, W. E. M., editor. (1987). Proceedings of the AOCS Short Course on Polyunsaturated Fatty Acids and Eicosanoids. American Oil Chemists' Society, Champaign, Ill.; Iigo, M. et al. (1997) Br. J. Cancer 75:650]. The potential of ω-3 PUFAs for preventative actions in cardiovascular diseases was recently supported by the finding that major dietary ω-3 PUFAs, such as eicosapentaenoic acid (C20:5 ω-3; EPA) and docosahexaenoic acid (C22:6 ω-3; DHA), have a dramatic effect on ischemia-induced ventricular fibrillation [Billman, G. E. et al. (1999) Circulation. 99:2452]. Emergence of such possible preventative and/or therapeutic actions of ω-3 PUFA supplementation in infant nutrition, cardiovascular diseases, and mental health has led to a call for recommended dietary intakes by an international workshop [Simopoulous, A. P. et al. (1999). J. Am. Coll. Nutr. 18:487]. The Gruppo Italiano per lo Studio della Sopravvivense nell 'Infarto Miocardio (GISSI) Prevenzione trial evaluated the effects of ω-3 PUFA supplementation with 11,300 patients surviving myocardial infarction taking ˜1 g of ω-3 PUFA daily (n=2,836) along with recommended preventive treatments including aspirin, and reported a significant benefit with a decrease in cardiovascular death [Marchioloi, R. et al. (1999). Lancet. 354:447]. However, the mechanisms underlying the protective action of dietary ω-3 PUFAs in these studies and other studies including those concerned with diseases of the skin, bowel, and neural tissues are not currently understood. One of the many hypothesized elements of the mechanism(s) of action of ω-3 PUFAs is that naturally occurring metabolites, formed from these PUFAs, may act as mediators that provide important biological functions, but these metabolites may have relatively short half-lives in vivo. There remains a need for new analogues which may have greater in vivo stability than naturally occurring ω-3 PUFA metabolites for settings where a longer half-life may be advantageous.